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Sildenafil, tadalafil, and vardenafil are phosphodiesterase type 5 enzyme (PDE-5) inhibitors used for the treatment of male erectile dysfunction. This present study aims to investigate 55 herbal products indicated for men’s sexual health from the Malaysian market for adulteration of PDE-5 inhibitors and analogues. The screening and identification of 20 PDE-5 inhibitors and analogues in herbal products of various forms (powder, capsules, tablets, and pastels) were conducted using gas chromatography–electron impact-mass spectrometer (GC-EI-MS). The analysis has shown that 19 herbal products were adulterated with PDE-5 inhibitors and analogues. Unique ion fragmentations and the presence of molecular ion serve as potential markers, and the limit of detection (LOD) was 0.1-5.0 µg/g. Ten PDE-5 inhibitors and analogues were randomly selected and successfully validated for simultaneous quantification, whereby the limit of quantitation (LOQ) was 5.0–50.0 µg/g with recoveries at 86.1-118.9%. The developed method of GC-EI-MS was shown to be simple, throughput, economical and had sufficient sensitivity to screen, identify and quantify PDE-5 inhibitors and analogues in herbal matrices.

Chlorfluazuron (CFZ) is a benzoylphenylurea insecticide that is commonly used in baits for management of subterranean termites. In this study, a new method using GC-MS for the determination and quantification of CFZ in termites was developed and validated. Since a small volume of organic solvent (250 µL) was used in the sample preparation procedure, the extract was analyzed without any evaporation. The assay was simple and rapid, with a short GC run time (10.0 min). The calibration curve was linear over the range of 0.1-2.5 µg/g, and the correlation coefficient was >0.998. This method was sensitive, as demonstrated by the detection and quantification limits of 0.003 µg/g and 0.1 µg/g, respectively. The mean recovery of CFZ from spiked samples was 95.6%. The within-day and between-day precision and accuracy of the assays ranged between 1.19 and 6.43%. This method was used to screen for CFZ transfer between nestmates of a treated Macrotermes gilvus mound. The highest amount of CFZ was detected in workers from the royal chamber, followed by workers in the peripheral zone, workers in the nursery zone, larvae in the nursery zone, and larvae in the peripheral zone.